Piston check valve

ABSTRACT

A check valve includes a valve housing having a valve cover, a valve seat and spring loaded valve diaphragm with a valve spindle, and base for the valve spindle. The free end of the spindle is made in the form of a piston and the valve spindle cover is in the form of a cylinder through which a blast of control gas enters.

United States Patent [15] 3,684,006 Spahn [451 Aug. 15, 1972 PISTONCHECK VALVE [56] References Cited [72] Inventor: Walter Spahn, c/oMesser UNITED STATES PATENTS Grleshelm GmbH Frankfun/Mmn, 2,734,5652/1956 Lochman ..165/97 Germany [22] Filed: June 1, 1970 PrimaryExaminer-Charles Sukalo [2i] Appl. No.: 42,276 Attorney-Connolly andHutz [30] Foreign Application Priority Data [57] ABSTRACT J e 3, 19 9Germany p 19 2 1301 A check valve includes a valve housing having avalve cover, a valve seat and spring loaded valve diaphragm [52] US. Cl..l65/97 with a valve spindle, and base for the valve spindle. [51] Int.Cl. ..F28[ 27/02 The free end of the spindle is made in the form of a[58] Field of Search ..l65/5, 95, 97

piston and the valve spindle cover is in the form of a cylinder throughwhich a blast of control gas enters.

4 Claims, 4 Drawing Figures PATENTEDAUB 15 I972 3,684,006

sum 2 or 4 Fig. 2

PATENTEU 3,684,006

SHEET F 4 Fig; 4

BACKGROUND OF INVENTION The invention concerns a check valve which isparticularly adapted for incorporation in installations for lowtemperature technics, for example, the separation of air componnents(air reduction). In such equipment reversible plate heat exchangers orregenerators are used, at the cold end of which a check valve isinserted which connects the ports of the heat exchanger or theregenerator with the input and output pipes. With each reversal one halfof the check valve is closed and the other half opened.

Such check valves consist in principle of a valve housing with a valvecover and valve seat upon which a spring loaded valve diaphragm rests.On opening of the valve, the force of the flowing medium must exceed theresistance of the spring compressing it thereby raising the valvediaphragm from its seat. When the pressure of the flowing medium isstill too small, the spring is only partially compressed and the entirecross-sectional area of the valve is not opened. In this case there isgreat pressure loss, especially when an oversized valve is employed.

SUMMARY OF INVENTION An object of this invention is to solve the aboveproblem by construcing a check valve, which, independent of pressure orvolume of the flowing medium always opens to the total cross-sectionalarea of the valve.

A check valve has been found, which consists of a valve housing, a valvecover, a valve seat and a spring loaded valve diaphragm with a valvespindle and a housing for the spindle. According to the invention, thefree end of the valve spindle is formed into a piston and the valvespindle housing in this region is constructed as a cylinder; the pistonis impelled by a sudden puff or burst of controlling gas through anopening in the valve cover.

Especially advantageous is the incorporation of a check valveconstructed according to this invention at the cold end of a reversibleplate heat exchanger or regenerator when the flowing medium is underdifferent high pressures. In this case the flowing medium itself can beused as the controlling gas. The check valves according to the inventionare simple in construction and sure in function. Also in very smallvolume flow they open to the maximum cross-sectional area withcertainty.

THE DRAWINGS FIG. 1 is a cross-sectional view of one embodiment of thisinvention;

FIG. 2 is a cross-sectional view of a further embodiment of thisinvention;

FIG. 3. is a cross-sectional view of still another embodiment of thisinvention; and

FIG. 4 is a schematic showing of an arrangement incorporating a checkvalve, constructed according to this invention, at the cold end of areversible plate heat exchanger or regenerator of an air reductioninstallatron.

DETAILED DESCRIPTION In the embodiment according to FIGS. 1-3 like partswith the same function have like reference numerals.

The check valve according to FIG. 1 consists essentially of the valvehousing 1 with the valve seat 2 and the valve cover 6, as well as valvediaphragm 3 with the valve spindle 7. The valve spindle 7 is enclosed inthe valve spindle housing 8 which is rigidly jointed to the valve cover6. The jointure can be made with bolts or screws, as valve seat 2 isfastened with bolt 9, the valve diaphragm with screw 10, and the valvecover with screw 11. The position of the valve diaphragm 3 is shown openand also closed. The direction of medium is indicated by means of anarrow 12. The check valve is pictured as an angle valve, because thisshort form is often advantageous. It is apparent that the invention isnot limited to this form of construction.

According to this invention the free end of the valve spindle 7 isformed as the piston 4 and the corresponding place of the valve spindlehousing 8 is constructed as cylinder 5. Piston 4 and cylinder 5 are hitwith a con trolling stream of gas through a control opening 13 in thevalve cover: Because small losses due to leaks are permissible thepiston moves in the dry cylinder 14 and is furnished with a thick seat15 at the end. Piston rings are therefore not necessary. A spring 16,concentrically situated on the valve spindle 7 between the base 8 of thevalve spindle and the piston so that the check valve, when not beingdriven by the controlling gas, is in the closed position. To open thevalve a controlling gas is needed which has a higher pressure than themedium flowing through the valve. This higher pressure of the controlgas must not fall below a definite minimal value if the valve is to openpositively. This minimal pressure is easily determined from the data athand, as the pressure of the medium flowing through the valve, weight ofthe valve diaphragm and valve spindle, inner cylinder and pistonfriction, spring constants and diameter of the piston. In reverse thevalve can be easily adjusted to a given control gas with a stableminimal pressure when a suitable spring and a sufficiently large pistondiameter are chosen.

A bolt 17 projects into a nut on the valve spindle 7 and secures itagainst turning. A bore 19 serves to exhaust the space beneath thepiston 4.

The check valve in FIG. 2 corresponds in large measure to that inFIG. 1. In this embodiment the valve diaphragm 3 is on the same side asthe valve seat 2, as the piston 4, and the spring 16; that is, in thespace between the valve seat 2 and the valve cover 6.

With this arrangement the valve is closed when not being driven; thespring 16 must be arranged differently from that of FIG. 1; that is, itmust be between piston 4 and valve cover 6. The spring 16 then isinserted in a recess in piston 4. There are of course, numerous otherconstructions possible with the spirit of this invention. With theembodiment of FIG. 2 the impact on piston 4 and cylinder 5 by thecontrolling gas follows at a lower pressure than that of the mediumflowing through the valve. Here also there is a definite limiting valuefor the pressure of the controlling gas, entirely analagous to thesituation in the description of FIG. 1.

IN FIG. 3 there is a special form illustrated for a check valve which inlarge measure resembles that described under FIG. 2 in which, however,the spring 16 is arranged, as in the embodiment of FIG. 1,concentrically on the valve spindle 7 between piston 4 and the base ofthe valve spindle 8. As a result this valve is open when not being actedupon by the controlling gas.

FIG. 4 shows a combination of check valves accordirrg to the inventionat the cold end of a reversible plate heat exchanger or regenerator ofan air reduction installation.

As schematically shown therein, two passages of the plate heat exchangeror regenerator are designated as 20 and 21. Cold nitrogen at lowpressure fills passage 20 and passes into the exchanger via the pipe 22there to release its cold air, or in other words to absorb heat. Inpassage 21 there is still air under high pressure which is to be cooledin the exchanger and flow into the reduction apparatus through pipe 23.By means of a connection device (not illustrated) the passages 20 and 21are exchanged from time to time. In relation to this action four valvesare provided, two nitrogen valves 24 and 26 and two air valves 25 and27. The nitrogen valves 24 and 26 correspond to the valve illustrated inFIG. 1, and the air valves 25 and 27 to the one described in FIG. 2. Thevalves 24 and 25 are connected with the nitrogen passage 20 by shortpieces of pipe 28 and 29, the valves 26 and 27 through correspondingpieces of pipe 30 and 31 with the air passage 21. The air valves 25 and27 open through pipes 33 and 35 into the pipe 23; the nitrogen valvesare connected through pipes 32 and 34 with pipe 22. Further, the controlopenings of valves 24 and 25 are connected by the control pipe 39 withthe air passage 21. Correspondingly the control openings valve 26 and 27are connected through a control pipe 36 with the nitrogen passage 20.The direction of flow of nitrogen is indicated by arrow 37, that of theair by arrow 39.

In the type of connection illustrated in FIG. 4 the nitrogen valve 24and the air valve 27 are open, and the other two valves are closed. Thecylinders of valves 24 and 25 of the nitrogen passage are struck by thehigh pressure of the air in the air passage 21 through the control pipe35. The cylinders 26, 27 of the air passage 21, connected through thecontrol pipe 36 are struck by the lower pressure of nitrogen in thenitrogen passage 20.

The piston of the air valve is struck from above and below by air and istherefore non-functional. The valve 25 becomes closed through thepressure of the spring and the pressure of the air on the valvediaphragm.

The piston of the nitrogen valve 24 is struck from above by air and frombelow by nitrogen; it is pushed down against the pressure of the springand the valve 24 opens. The opening of the e valve 24 is supported bythe pressure of the flowing nitrogen; however, this support is notnecessary. Even when the volume flow of nitrogen is very small, themaximal cross-sectional area of the valve is opened.

The piston of the air valve 27 is struck by nitrogen from above and frombelow by air; therefore there is a relatively lower pressure in thecylinder and the piston is pushed upward against the pressure of thespring, so that valve 27 is opened. The opening of valve 27 is supportedby the pressure of the flowing air. This support is, however, notrequired, as with a smaller volume flow of air the entirecross-sectional area of the valve is opened.

The piston of the nitrogen valve 26 is closed by means of the pressureof the spring and the force of the air on the valve diaphragm.

It is obvious that by the switching of the passages, the

function of valves 24 and 27 is exchanged with the function of valves 25and 26; the maximal opening of the valves always occurs. The valvediaphragm can be controlled in a purely mechanical manner as the valvespindle might be extended to the exterior through valve cover instead ofcontrol by the piston and the associated piping. Aside from a morecomplicated construction, such a solution would be disadvantageous onaccount of the greater loss of cold through heat conduction over thevalve spindle. The installation of the check valves made according tothis invention at the cold end of reversible plate heat exchangers orregenerators is especially advantageous, above all, when the flowingmedia are under difierent high pressures which can be used directly forcontrol of the valves. The invention is, however, in no way limited tothis particular use, as check valves made according to this inventioncan be constructed in most varied forms. The valves are simple inconstruction and their function can be altered by the exchange of only afew simple parts. They are very nearly free of wear and tear and need nospecial care. They always open to the total cross-sectional area.

What is claimed is:

l. A check valve comprising a housing, an inlet and an outlet in saidhousing, a valve housing cover on said housing, a valve seat in saidhousing between said inlet and said outlet, a spring loaded diaphragmpositioned for moving toward and away from said valve seat forcontrolling flow therethrough, said diaphragm being mounted on one endof a valve spindle, the other end of said spindle being constructed as apiston and being movable in a valve spindle cover, said spindle coverforming with said housing cover a cylinder for said piston, and anopening in said housing cover disposed in line with said piston wherebya blast of control gas may enter through said opening into said cylinderand against said piston to cause said piston to move in a forward strokefor actuating said diaphragm, in combination therewith, a plurality ofsaid check valves, a reversible plate heat exchanger or regeneratorsystem having means for inflowing medium and for outflowing medium, saidcheck valves being on the cold end of said system, a chamber for theinflowing medium and a chamber for the outflowing medium, each of saidchambers having an inlet and an outlet, one of said check valves beingdisposed in each of said inlets and said outlets, said inlet checkvalves being interconnected by a common supply pipe, said outlet checkvalves being interconnected by a common outflow pipe, the outflowingmedium having a higher pressure than the inflowing medium, saidinflowing medium check valves being connection for actuation control bythe outflowing medium, and said outflowing medium check valves beingconnected for actuation control by the inflowing medium.

2. The arrangement of claim 1 wherein each of said inlet valves has itsvalve seat disposed between its diaphragm and its piston, its spindlehaving a base member disposed on the same side of the valve seat as thepiston, and the spring for the diaphragm being concentrically mounted onits spindle and reacting between its base member and its piston.

3. The arrangement of claim 2 wherein each of said outlet valves has itsdiaphragm and spring and its piston all disposed between its valve seatand its housing cover, and the spring reacts between the piston and thehousing cover.

4. The arrangement of claim 3 wherein the openings in said inflowingmedium check valves are connected by a first control pipe to saidoutflowing medium chamber for actuating by the outflowing medium, andthe openings in said outflowing medium check valves are connected by asecond control pipe to said inflowing medium chamber for actuation bythe outflowing medium, and the openings in said outflowing medium checkvalves are connected by a second control pipe to said inflowing mediumchamber for actuation by the inflowing medium, said inflowing mediumflowing through said check valves at said inlet of each of said chamberswith said inlet check valves being openable by pressure, said outflowingmedium flowing through said check valves at said outlet of each of saidchambers with said outlet check valves being closable by pressure, saidinflowing medium flowing through said second control pipe forrespectively opening and closing the inlet and outlet valves of saidoutflowing medium chamber, and said outflowing medium flowing throughsaid first control pipe for respectively opening and closing the inletand outlet valves of said inflowing medium chamber.

1. A check valve comprising a housing, an inlet and an outlet in saidhousing, a valve housing cover on said housing, a valve seat in saidhousing between said inlet and said outlet, a spring loaded diaphragmpositioned for movinG toward and away from said valve seat forcontrolling flow therethrough, said diaphragm being mounted on one endof a valve spindle, the other end of said spindle being constructed as apiston and being movable in a valve spindle cover, said spindle coverforming with said housing cover a cylinder for said piston, and anopening in said housing cover disposed in line with said piston wherebya blast of control gas may enter through said opening into said cylinderand against said piston to cause said piston to move in a forward strokefor actuating said diaphragm, in combination therewith, a plurality ofsaid check valves, a reversible plate heat exchanger or regeneratorsystem having means for inflowing medium and for outflowing medium, saidcheck valves being on the cold end of said system, a chamber for theinflowing medium and a chamber for the outflowing medium, each of saidchambers having an inlet and an outlet, one of said check valves beingdisposed in each of said inlets and said outlets, said inlet checkvalves being interconnected by a common supply pipe, said outlet checkvalves being interconnected by a common outflow pipe, the outflowingmedium having a higher pressure than the inflowing medium, saidinflowing medium check valves being connection for actuation control bythe outflowing medium, and said outflowing medium check valves beingconnected for actuation control by the inflowing medium.
 2. Thearrangement of claim 1 wherein each of said inlet valves has its valveseat disposed between its diaphragm and its piston, its spindle having abase member disposed on the same side of the valve seat as the piston,and the spring for the diaphragm being concentrically mounted on itsspindle and reacting between its base member and its piston.
 3. Thearrangement of claim 2 wherein each of said outlet valves has itsdiaphragm and spring and its piston all disposed between its valve seatand its housing cover, and the spring reacts between the piston and thehousing cover.
 4. The arrangement of claim 3 wherein the openings insaid inflowing medium check valves are connected by a first control pipeto said outflowing medium chamber for actuating by the outflowingmedium, and the openings in said outflowing medium check valves areconnected by a second control pipe to said inflowing medium chamber foractuation by the outflowing medium, and the openings in said outflowingmedium check valves are connected by a second control pipe to saidinflowing medium chamber for actuation by the inflowing medium, saidinflowing medium flowing through said check valves at said inlet of eachof said chambers with said inlet check valves being openable bypressure, said outflowing medium flowing through said check valves atsaid outlet of each of said chambers with said outlet check valves beingclosable by pressure, said inflowing medium flowing through said secondcontrol pipe for respectively opening and closing the inlet and outletvalves of said outflowing medium chamber, and said outflowing mediumflowing through said first control pipe for respectively opening andclosing the inlet and outlet valves of said inflowing medium chamber.